Retail is a process involving payment against the supply of goods and/or services. In automatic retail, both supply and payment do not require human attendance. Prior art automatic retail is usually based on the controlled-supply concept, i.e. the customer deposits a sum, the automatic retail system controls the supply of merchandise items chosen by the customer for a total cost within this sum, and upon purchase completion the unused part of the deposited sum is returned. Common vending machines and public telephones are examples of controlled supply automatic retail systems. There are also known in the art prior art cashless payment means. These include payment cards, such as the electronic checkbook (i.e. a credit card or a bank debit card) for charging a credit or bank account, the electronic purse which is a rechargeable stored-value card, loaded with a sum at dedicated replenishment devices and depleting the loaded sum on payment, and the combo smart card, (termed here "electronic wallet"). The electronic wallet includes both an electronic checkbook and an electronic purse. The execution of electronic checkbook transactions is relatively costly, and can be justified only for transactions which exceed a predefined minimum size; transactions whose value is below this minimum can be executed with the electronic purse. Present use of payment cards, in particular the use of electronic wallets, is associated with many deficiencies, a few examples of which are provided herein below:
a. Since electronic wallets are depleted at each payment, the customer must execute regularly purse replenishment transactions at suitable replenishment devices, which is inconvenient.
b. An electronic wallet may occasionally fail to pay for a purchase whose value is higher than the current balance in the electronic purse but is still below the minimum value allowed for the electronic checkbook.
c. Automatic controlled-supply purchases, e.g. a public telephone call or filling a gas tank, may be interrupted at any time when the electronic purse is exhausted.
d. To reduce the inconvenience, failure and interruption described above, many customers tend to overload their electronic purse during replenishment transactions, which reduces the interest-bearing deposit in the bank, and in electronic purse systems which do not employ audit retail, increases the damage when an electronic wallet is lost.
e. Electronic purse operation requires setting up a costly infrastructure of replenishment devices, such as special ATMs (automatic teller machines), modified public telephones or dedicated home terminals.